Modbus Data/Communication Issue

D. Wubben

I have an 8864 logger communicating Modbus with 2 devices. I don't know Modbus at all. However, my file appears to read/write from one device and then go on to the next. This doesn't always happen to the same device, either. When I have the issue with data values being zeros, I can unplug the Ethernet connection for a minute and plug it back in. This usually allows communication to commence. Sometimes it lasts for a minute or two and other times it can be for hours or days (weekends). It only happens once every couple of months. I think I should add that it goes Ethernet to fiber optic to Ethernet and back Ethernet to fiber optic to Ethernet again.

Deanna Wubben

The system that the values are read from has good values when I export the file. I then have to use the exported file to fill in the zero values in my DAHS. The only way I can explain this is to say the communication gets into a traffic jam. When I unplug the cable, it seems to clear the traffic jam and allows the good values to begin to flow again.